diff mbox series

[v6] vhost_net: avoid tx queue stuck when sendmsg fails

Message ID 1610012985-24868-1-git-send-email-wangyunjian@huawei.com
State New
Headers show
Series [v6] vhost_net: avoid tx queue stuck when sendmsg fails | expand

Commit Message

wangyunjian Jan. 7, 2021, 9:49 a.m. UTC 
From: Yunjian Wang <wangyunjian@huawei.com>

Currently the driver doesn't drop a packet which can't be sent by tun
(e.g bad packet). In this case, the driver will always process the
same packet lead to the tx queue stuck.

To fix this issue:
1. in the case of persistent failure (e.g bad packet), the driver
   can skip this descriptor by ignoring the error.
2. in the case of transient failure (e.g -ENOBUFS, -EAGAIN and -ENOMEM),
   the driver schedules the worker to try again.

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
---
v6:
   * update code styles and commit log
---
 drivers/vhost/net.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

Comments

Jakub Kicinski Jan. 8, 2021, 12:56 a.m. UTC | #1 
On Thu, 7 Jan 2021 17:49:45 +0800 wangyunjian wrote:
> From: Yunjian Wang <wangyunjian@huawei.com>

> 

> Currently the driver doesn't drop a packet which can't be sent by tun

> (e.g bad packet). In this case, the driver will always process the

> same packet lead to the tx queue stuck.

> 

> To fix this issue:

> 1. in the case of persistent failure (e.g bad packet), the driver

>    can skip this descriptor by ignoring the error.

> 2. in the case of transient failure (e.g -ENOBUFS, -EAGAIN and -ENOMEM),

>    the driver schedules the worker to try again.

> 

> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>


Hi! AFAIU this needs to go to net-next. You need to wait until net is
merged into net-next and then repost. It doesn't apply at the moment
and we get in excess of 100 patches a day right now so keeping track 
of dependencies on the maintainer side does not work. Also build bot
can't test it.

net should get merged into net-next some time tomorrow or on Saturday.
diff mbox series

Patch

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index c8784dfafdd7..bfe2f0f2084b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -827,14 +827,15 @@  static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
 				msg.msg_flags &= ~MSG_MORE;
 		}
 
-		/* TODO: Check specific error and bomb out unless ENOBUFS? */
 		err = sock->ops->sendmsg(sock, &msg, len);
 		if (unlikely(err < 0)) {
-			vhost_discard_vq_desc(vq, 1);
-			vhost_net_enable_vq(net, vq);
-			break;
-		}
-		if (err != len)
+			if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) {
+				vhost_discard_vq_desc(vq, 1);
+				vhost_net_enable_vq(net, vq);
+				break;
+			}
+			pr_debug("Fail to send packet: err %d", err);
+		} else if (unlikely(err != len))
 			pr_debug("Truncated TX packet: len %d != %zd\n",
 				 err, len);
 done:
@@ -922,7 +923,6 @@  static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
 			msg.msg_flags &= ~MSG_MORE;
 		}
 
-		/* TODO: Check specific error and bomb out unless ENOBUFS? */
 		err = sock->ops->sendmsg(sock, &msg, len);
 		if (unlikely(err < 0)) {
 			if (zcopy_used) {
@@ -931,11 +931,13 @@  static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
 				nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
 					% UIO_MAXIOV;
 			}
-			vhost_discard_vq_desc(vq, 1);
-			vhost_net_enable_vq(net, vq);
-			break;
-		}
-		if (err != len)
+			if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) {
+				vhost_discard_vq_desc(vq, 1);
+				vhost_net_enable_vq(net, vq);
+				break;
+			}
+			pr_debug("Fail to send packet: err %d", err);
+		} else if (unlikely(err != len))
 			pr_debug("Truncated TX packet: "
 				 " len %d != %zd\n", err, len);
 		if (!zcopy_used)